Energy harvesting system with wavelength-selective energy scattering layer

ABSTRACT

A particularly-formed multi-layer micron-sized particle is provided that is substantially transparent, yet that exhibits selectable coloration based on its physical properties. The disclosed physical properties of the particle are controllably selectable refractive indices to provide an opaque-appearing energy transmissive material when pluralities of the particles are suspended in a substantially transparent matrix material. Multiply-layered (up to 30+ constituent layers) particles result in an overall particle diameter of less than 5 microns. The material suspensions render the particles deliverable as aspirated or aerosol compositions onto substrates to form layers that selectively scatter specific wavelengths of electromagnetic energy while allowing remaining wavelengths of the incident energy to pass. The disclosed particles and material compositions uniquely implement optical light scattering techniques in energy (or light) transmissive layers that appear selectively opaque, while allowing 80+% of the energy impinging on the light incident side to pass through the layers.

This application is a continuation of U.S. patent application Ser. No.15/415,851 entitled “COMPOSITIONS OF MATERIALS FOR FORMING COATINGS ANDLAYERED STRUCTURES INCLUDING ELEMENTS FOR SCATTERING AND PASSINGSELECTIVELY TUNABLE WAVELENGTHS OF ELECTROMAGNETIC ENERGY”, filed in theUSPTO on Jan. 25, 2017; which is related to U.S. patent application Ser.No. 15/415,857, entitled “Methods For Making Compositions Of MaterialsFor Forming Coatings And Layered Structures Including Elements ForScattering And Passing Selectively Tunable Wavelengths OfElectromagnetic Energy,” and Ser. No. 15/415,864, entitled “DeliverySystems And Methods For Compositions Of Materials For Forming CoatingsAnd Layered Structures Including Elements For Scattering And PassingSelectively Tunable Wavelengths Of Electromagnetic Energy,” each ofwhich was filed on Jan. 25, 2017, a same day as this application; thedisclosures of all of the above are hereby incorporated by referenceherein in their entirety.

BACKGROUND 1. Field of the Disclosed Embodiments

This disclosure describes particularly-formed multi-layer micron-sizedparticles that are substantially transparent, yet that exhibitselectable coloration based on their physical properties and the mannerin which the particles are formed to produce certain optical propertiesin layers formed of the particles. Layers formed of the disclosedparticles and material compositions selectively scatter specificwavelengths of electromagnetic energy back in an incident directionwhile allowing remaining wavelengths to pass therethrough, includinguniquely implementing optical light scattering techniques in energy (orlight) transmissive layers to make those layers appear opaque whenobserved from a light incident side, while allowing at least 50%, and asmuch as 80+%, of the energy impinging on the light incident side to passthrough the layer.

2. Related Art

An ability to provide or promote selective transmission ofelectromagnetic energy, including light in the visual or near-visualradiofrequency (RF) spectrum, through layers, materials, structures orstructural components provides substantial benefit in a number ofreal-world use cases and applications. U.S. patent application Ser. No.15/006,143 (the 143 application), entitled “Systems and Methods forProducing Laminates, Layers and Coatings Including Elements forScattering and Passing Selective Wavelengths of Electromagnetic Energy,”and Ser. No. 15/006,145 (the 145 application), entitled “Systems andMethods for Producing Objects Incorporating Selective ElectromagneticEnergy Scattering Layers, Laminates and Coatings,” each of which wasfiled on Jan. 26, 2016, and the disclosures of which are herebyincorporated by reference herein in their entirety, describe a basicstructure for forming such selectively energy transmissive layers, andcertain real world use cases in which those layers may be particularlyadvantageously employed. The 143 and 145 applications discuss, asbackground, conventional methods for modifying windows, skylights andthe like to limit, filter or otherwise modify an amount of light thatis, or constituent wavelengths of the light that are, transmitted intothe structure via these windows and/or skylights. The modifications tothe formerly transparent structures may limit an ability to see througha particular window or skylight to address privacy, security and/orother related concerns. The 143 and 145 applications discussconventional techniques that, whether implemented to address simpleaesthetics, or for other reasons, modify the light transmissiveproperties of the windows, skylights and/or constituent panels or panessubstantially in both directions equally.

The 143 and 145 applications describe other techniques for modifyingsome light transmissive properties in certain structural panelsincluding, for example, what are alternatively referred to as one-way ortwo-way mirrors, and certain high-end vehicle window tinting. Again hereit is noted that the light always passes through the mirror or tintedwindow exactly equally in both directions. Thus, the principle ofoperation is to keep one side brightly lit rendering that side“difficult” to see through based on the principle that the reflectedlight masks visual penetration of the mirror from the brightly lit side.The coatings or embedded layers, which are applied to, or included in,the mirror or window panels, ensure that a substantial portion of theincident light is reflected back from the “lighted” side of the mirroror tinted window, adversely affect the light transmissive properties ofthe ambient light incident to the lighted side of the mirror or tintedwindow as it passes through the panel.

The 143 and 145 applications note that in recent years, the fields ofenergy harvesting and ambient energy collection have gainedsignificantly increased interest. The 143 and 145 applications discussphotovoltaic (PV) cell layers and other photocell layers, including thinfilm PV-type (TFPV) material layers, that are advantageously employed onouter surfaces of particular structures to convert ambient light toelectricity. The efficiency of a particular PV layer is affected by itscapacity to absorb, and/or to minimize reflectance of, incident light onthe surface of the layer. For this reason, photocells and PV lightabsorbing material layers are generally formed to have dark, normallyblack or dark grey, exposed light-facing or light-incident (“facial”)surfaces. Maximum conversion efficiencies in operation of the PV layers(upward to 28+%) are achieved when the dark facial surfaces of these PVlayers are exposed to unfiltered light in the visible, or near-visible,spectrum. While experimentation has been undertaken with other forms of,for example, thin film PV layers including transparent thin-films, theconversion efficiencies for these non-conventional (or non-black) layersfall to as low as approximately one third the conversion efficiencies ofthose of the conventional dark facial surfaces generally associated withphotovoltaic cell layers. It is for this reason that, in virtually allconventional and most emerging installations, the PV layers are mountedunmodified on external surfaces of structures either (1) fully exposed,or (2) exposed behind clear (or substantially clear) glass, plastic orsimilar clear (substantially light transparent) protective outer surfacelayers that transmit the visual, or near-visual light, in an unmodifiedmanner from the light-incident side of such protective layers to thedark facial surfaces of the PV layers. Any such protective outer surfacelayers may provide some protection against adverse environmental effectsand/or damage to facial surfaces of the PV layers, which tend to becomparatively fragile, but they provide generally no manner by which tomodify the unfortunate aesthetic drawbacks presented by typical PV cellinstallations.

The 143 and 145 applications note that significant drawbacks to widerproliferation of photocells used in a number of potentially beneficialoperating or employment scenarios are that such “required”installations, in many instances, adversely affect the aesthetics of thestructure, object or host substrate surface on which the PV layers aremounted for use. Put another way, it is known that PV layers typicallymust be visible, in a substantially unimpeded, and/or unfiltered, mannerto surrounding ambient light. It is further known that the visualappearance of the PV layers cannot be significantly altered from thecomparatively dark greyscale to black presentations provided by thefacial surfaces without rendering the photocells significantly lessefficient, substantially degrading their operation. Presence ofphotocells and PV layers in most installations is, therefore, easilyvisually distinguishable, often in an aesthetically distracting ordegrading manner. Based on these drawbacks and/or limitations, inclusionof photocell arrays, and even sophisticated thin film PV layers, isoften avoided in many installations, or in association with manystructures, objects or products, which may benefit from the electricalenergy harvesting capacity provided by these layers. As such, photocelland other PV layer installations often become unacceptable visualdetractors or distractors adversely affecting the appearance orornamental design of the structures, objects or products on which thelayers may be otherwise advantageously applied and employed.

SUMMARY

The 143 and 145 applications introduce systems and methods that provideparticularly formulated energy or light transmissive overlayers. Theseoverlayers, generally in the form of surface treatments and/orcoverings, are formulated to support unique energy transmission andlight refraction schemes to effectively “trick” the human eye intoseeing a generally opaque presentation of the surface when observed froma light incident side. These overlayers are formulated to supporttransmission of visual light, or near-visual light, in a manner thatallows a substantial percentage of the electromagnetic energy topenetrate the surface treatments and coverings in a comparativelyunfiltered manner. Although particularly advantageously employed tosupport displayed visual optical effects, the principles according tothis disclosure may be equally applicable to filtering wavelengths ofelectromagnetic energy lying outside the visual spectrum. The materialcompositions disclosed in the 143 and 145 applications, while important,and useful in many operational employment scenarios, are constrained inthe manner in which the disclosed layers can be applied. Improvements onthe layer compositions disclosed in those applications may providegreater latitude in the manufacturing processes by which objectsincluding the disclosed particularized layers may be formed.

The 143 and 145 applications disclose advanced light scattering layersthat are usable as object outer layers, systems for forming those outerlayers and layer forming processes that provide particularly-adaptedstructures and light scattering layers that appear “opaque” from anouter, viewing, observation or energy/light-incident side, but thatotherwise provide a comparatively or substantially un-filteredenergy/light transmissive property rendering the thus-formed layers,objects and/or object outer layers substantially energy/lighttransparent, as viewed from an inside of the formed object or from anopposite or non-energy/light-incident side of the formed structurallayer or outer layer.

The energy transmissive layers disclosed in the 143 and 145 applicationsrely on a particular cooperation between refractive indices of thedisclosed micron-sized particles or spheres with cooperating refractiveindices of the matrix materials in which those micron-sized particlesare suspended for deposition on prepared surfaces. This coincidentrequirement between the refractive indices of the matrix material on therefractive indices of the suspended particles limits deposition of thesematerial suspensions of particles on substrates to techniques in whichthe deposition of the materials can be carefully controlled.

It would be advantageous to develop techniques by which to providesuspended micron-sized particles in a manner that controls therefractive indices of the developed layers regardless of a deliverymethod by which the suspensions of micron-sized particles are depositedonto a broad spectrum of substrate surfaces.

Exemplary embodiments of the systems and methods according to thisdisclosure may improve upon the inventive concepts disclosed in the 143and 145 applications by controlling the refractive indices of theparticles themselves to capture all of the physical parameters leadingto independent color selection.

Exemplary embodiments may provide substantially transparent micron-sizedparticles having a multi-layered structure in which refractive indicesof the constituent elements/layers of which the multi-layered particlesare controlled to produce repeatable coloration in the substantiallytransparent micron-sized particles.

Exemplary embodiments may provide a substantially clear outer layer onthe multi-layered structure of the substantially transparentmicron-sized particles in a manner that assures thatparticle-to-particle refraction interference is minimized.

Exemplary embodiments may provide matrix agnostic coloration particlesallowing for the suspension of such particles in any clear orsubstantially clear (or transparent) matrix material, which may be thenspecially formulated to support other physical parameters with respectto the layers formed of the substantially transparent micron-sizedparticles. Such physical parameters may include, but are not limited to,toughness and durability of the finished layers, adhesion/adherence ofthe layers to a particular substrate, and/or particular curingtechniques (heat curing, photo curing, and other like techniques) of thelayers on respective substrates.

Exemplary embodiments may provide particle suspensions that are amenableto being entrained in airstreams for aspirated and/or aerosol deliveryof the micron-sized particles in suspension onto various substratesurfaces.

Exemplary embodiments may provide delivery systems and methods forspraying particles suspensions onto various surfaces, and for promotingthe formation, development, fixing and/or finishing the electromagneticenergy (or light) transmissive layers on all forms of substrates withwide latitude in the selection of aspirated and/or aerosol deliverydevices.

Exemplary embodiments may form individual energy scattering layers outof substantially-transparent micron-sized particles, includingnanoparticles, which may be particularly overcoated in substantiallyenergy-neutral layers that control a minimum spacing of the colorationlayers of the particles so as to substantially eliminate micro- and/ornano-voids between the particles and yet control spacing of thecoloration components of the particles so as to reduceparticle-to-particle refractive interference.

In embodiments, refractive indices of the individual particles may becontrolled by a layered composition of a structure of the particles thatmay be tunable according to a controlled forming process in order thatthe finished layers may provide a selectively-opaque appearance whenviewed (or exposed to incident energy) from an energy/light incidentside.

In embodiments involving scattering of light in the visual range, aselectively-opaque appearance may be rendered according to an individualuser's desires, while the scattering layers aresubstantially-transparent to other wavelengths of energy/light passingthrough the finished layers to areas or sensors behind those finishedlayers according to tuned refraction of the individual particles. Suchstructures may allow the formed layers to substantially pass at least50% to in excess of 80% of the incident light through the layers toimpinge upon photovoltaic, energy absorbing, light responsive, orlight-activated components, energy harvesters, or sensors positioned ona non-light incident side of such layers.

Exemplary embodiments may provide systems, methods, schemes, processesor techniques by which volumes of light scattering particles, suspendedin solution or otherwise, may be entrained in an airstream or othergaseous delivery stream for aerosol or aspirated “spray” delivery ontoan object or substrate surface.

In embodiments, because the energy/light scattering layers are comprisedof substantially-transparent components (particles and fixing matrices),there is virtually no restriction on a particular environment, or to aparticular use, in which the layers and/or objects formed of the layersmay be operatively deployed for use.

In embodiments, a surface, or surface layer, that appears opaque whenviewed from the viewing, observation or light incident side may be madeto appear formed of a material of a particular color, or to include aparticular pattern, including a multi-color pattern, at the discretionof the user forming the object or object layer.

In embodiments, an appearance of a photocell array, or a thin-film PVlayer, may be enhanced by overcoating with a protective layer or filmthat is particularly arranged to allow an appearance of the photocellarray, or thin-film PV layer, to be masked behind the protective layeror film thereby outwardly presenting one or more of a wide range ofchosen colors and/or chosen patterns in a manner that does notsubstantially disrupt or degrade an efficient operation of the photocellarray, or thin-film PV layer.

These and other features, and advantages, of the disclosed systems andmethods are described in, or apparent from, the following detaileddescription of various exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the disclosed substantially transparentmulti-layer micron-sized particles, material compositions includingthose particles, and the systems and methods for delivering thosematerial compositions to form electromagnetic energy transmissive layersthat, once formed, selectively scatter specific wavelengths ofelectromagnetic energy while allowing remaining wavelengths to passtherethrough, including uniquely implementing optical light scatteringtechniques in such energy transmissive layers, and with respect toobjects, object portions, structural components, foldable/rollablesubstrates and the like that may benefit from being coated with, formedof or that otherwise incorporate, such transmissive energy-scatteringlayers, will be described, in detail, with reference to the followingdrawings, in which:

FIG. 1 illustrates a schematic diagram of an exemplary energy/lightscattering surface layer disposed on a structural body member substrateaccording to this disclosure;

FIG. 2 illustrates a schematic diagram of an exemplary laminatedsubstrate surface energy harvesting component including, as one or moreof the laminate layers, a thin-film photovoltaic layer disposed on asubstrate, and an energy/light scattering layer according to thisdisclosure disposed over the thin-film photovoltaic layer;

FIG. 3 illustrates a schematic diagram of an exemplary autonomouscomponent for remote deployment and surveillance scenarios includingenergy-harvester power, light sensitive (or other physical parametermeasuring) sensor elements, processor, data storage and communicationcapabilities mounted in a structural body member having a surfaceconstituted of a light scattering surface layer according to thisdisclosure;

FIG. 4 illustrates an exemplary embodiment of a detail of anenergy/light scattering layer according to this disclosure;

FIG. 5 illustrates a schematic diagram of an exemplary detail of asubstantially transparent multi-layer individual micron-sized particleusable in a light scattering layer according to this disclosure;

FIG. 6 illustrates a schematic diagram of an exemplary assembly lineusable for automated forming of energy/light scattering surface layerson structural body members including photocell array layers according tothis disclosure; and

FIG. 7 illustrates a flowchart of an exemplary method for forming alight-scattering layer, as an autonomous structure, or on some manner ofenergy harvesting structural body member, having an opaque outwardappearance based on inclusion of an energy/light scattering surfacelayer formed over a photocell layer according to this disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The substantially transparent multi-layer micron-sized particles,material compositions in which those particles may be delivered, and thesystems and methods for delivery of those material compositions ontosubstrate surfaces according to this disclosure may include techniquesfor forming the substantially transparent multi-layer micron-sizedparticles, techniques for developing material compositions forsuspending the formed substantially transparent multi-layer micron-sizedparticles to facilitate delivery, and delivery systems and techniquesfor delivery of those material compositions to form electromagneticenergy transmissive layers. These layers, once formed, may selectivelyscatter specific wavelengths of electromagnetic energy impinging on anenergy incident side of the layers, while allowing remaining wavelengthsof the electromagnetic energy to pass therethrough. These layers mayuniquely implement optical light scattering techniques in such energytransmissive layers. The layers may be applied to objects, objectportions, structural components, solid material substrates,foldable/rollable material substrates and the like to produce aselectively colored or designed surface that effectively hides orcamouflages electromagnetic (or light) energy activated componentsplaced behind the layers. These layers may be particularly formed toselectively scatter particular wavelengths of electromagnetic energy,including light energy in the visual, near-visual or non-visual range,while allowing remaining wavelengths to pass therethrough with atransmissive efficiency of at least 50%, and up to 80+% with respect tothe impinging energy. These layers may uniquely employ optical lightscattering techniques in such energy-scattering layers comprised ofuniquely-formed substantially transparent multi-layer micron-sizedparticles that are sized typically on an order of comparable pigmentparticles found in conventional paints and colorants. Objectives of thedisclosed schemes, techniques, processes and methods may further includematerial build and/or coating techniques for forming objects, objectportions, object surfaces, lenses, filters, screens and the like thatinclude, or otherwise incorporate, such transmissive energy scatteringlayers and/or light scattering layers.

Descriptions of the disclosed systems and methods will refer to a rangeof real world use cases and applications for energy/light scatteringlayers, and/or for objects incorporating one or more energy/lightscattering layers, that are so formed. These may include, for example,what appear, in use, to be “painted” surfaces, with the distinctdifference that the surface treatments allow, rather than block, asubstantial portion of the energy impinging on an energy incident sideof the produced layers to pass through and to activate, for example,energy activated components underlying the layers.

Exemplary embodiments described and depicted in this disclosure shouldnot be interpreted as being specifically limited to any particularlylimiting material composition of the individually-describedsubstantially transparent multi-layer micron-sized particles, and thematrices in which those particles may be suspended, except as indicatedaccording to the material properties generally outlined below. Further,the exemplary embodiments described and depicted in this disclosureshould not be interpreted as specifically limiting the configuration ofany of the described layers or of structures, objects, object portions,object surfaces, substrates, articles of manufacture or componentsections thereof. Finally, references will be made to individual ones,or classes, of energy/light collecting sensor components andenergy/light activated devices that may be operationally mounted in,installed in or placed behind the disclosed energy/light scattering,light directing or light transmissive layers so as to be hidden fromview when an object including such sensor components or devices isviewed from a viewing, observation or light incident outer surface ofthe object or layer, from which perspective the energy/light scattering,light directing or light transmissive layers may appear “opaque” to theincident electromagnetic energy. These references are intended to beillustrative only and are not intended to limit the disclosed concepts,compositions, processes, techniques, methods, systems and devices in anymanner. It should be recognized that any advantageous use of thedisclosed schemes for preparing the disclosed particles, suspendingthose particles in a delivery matrix, and forming energy/lighttransmissive, light directing and/or light scattering layers, andobjects formed of, or otherwise incorporating, such layers to effect anaesthetically consistent, or aesthetically pleasing, outward appearanceof the object or layer while allowing particularly visible, ornear-visible, light components to pass through, employing systems,methods, techniques, and processes such as those discussed in detail inthis disclosure is contemplated as being included within the scope ofthe disclosed exemplary embodiments.

The disclosed systems and methods will be described as beingparticularly adaptable to hiding certain light-activated devices andsensors, and certain photovoltaic materials, cells or photocells(generally referred to below collectively as “photocells”), and anemerging class of increasingly efficient thin-film photovoltaic (“TFPV”)materials or material layers, which are typically mils thick, on thesurfaces of, or within objects, behind layers that may appear opaquefrom a viewing, observation or light incident side. As used throughoutthe balance of this disclosure, the term “photocell” will be employed asshorthand and intended to reference, without limitation, broad classesof light-activated, light-absorbing light-employing or otherwiseoperationally light-involved surfaces or components in which aphotoelectric, photoconductive or photovoltaic effect is advantageouslyemployed to produce a current or voltage when exposed to light (in avisual or near-visual range of the electromagnetic spectrum), or otherselected electromagnetic radiation. These references also incorporateTFPV materials and material layers. Those of skill in the art recognizethat photocells may be alternatively referred to as photoelectric cells,photovoltaic cells, or photoconductive cells, and more colloquially incertain implementations as “electric eyes.” The generic use of the termphotocell in this disclosure encompasses, without limitation, all ofthese terms as well.

Photocells are typically covered in silica crystalline, amorphous,thin-film, organic or other light directing layers. These lightdirecting layers work by implementing scattering and/or plasmoniceffects in which light absorption is improved generally by scatteringlight using metal nanoparticles excited at a surface plasmon resonanceof those nanoparticles. Surface plasmon resonance or SPR generallyrefers to a resonant oscillation of conduction electrons at an interfacebetween a negative and positive permittivity material when stimulated byincident light. A resonance condition is established when the frequencyof incident photons matches a natural frequency of surface electronsoscillating against a restoring force of positive nuclei.

In embodiments according to this disclosure, unique and advantageouslight directing layers scatter a small portion of an impinging lightspectrum back in a direction of an observer on a viewing, observation orlight incident side of the light directing layer. In this manner, aparticular light directing layer may appear to have a particular colorin the visual spectrum, while a substantial portion (at least 50% and upto 80+%) of the light energy permissibly passes through the thin lightdirecting layer impinging on an operative surface of the underlyingphotocell to produce electricity according to the photoelectric effect.

Reference may be made to the disclosed energy/light transmissive layers,energy/light scattering layers and/or energy/light directing layers, asthese terms may be interchangeably used in the context of thisdisclosure, being particularly usable to aesthetically hide photocells.It should be recognized, however, that the disclosed layers may beequally effective in employment scenarios, and/or use cases in whichother sensors, including some form of camera or imaging device or lenspositioned behind such a layer, may be usable for observation of a spaceor area. A capacity of such a camera or imaging device to be usable insubstantially all lighting conditions may be limited only by acapability of the camera or imaging device itself, and not limited basedon any failure of the light scattering layer behind which the camera orimaging device is placed to be substantially-transparent with respect tothe camera or imaging device. While the disclosed light-scatteringlayers do not produce a completely transparent lens through which imagesare captured, filtering may be applied between the layer and the lens torender the captured images adequate to many surveillance scenarios. Aposition of such a camera or imaging device behind the light scatteringlayer may be substantially “hidden,” or otherwise camouflaged, as may,in like manner, be a position of any number of light actuated detection,sensor or other device components. In this regard, general reference tothe use of the disclosed energy/light scattering layers, or objectsformed of those energy/light scattering layers, as embedding photocellsshould not be considered as limiting the disclosed systems and methodsto any particular set or class of light-activated or light employingsensors. Further, while general reference will be made to “lightscattering” effects, these references are not intended to exclude energyscattering in other portions of the electromagnetic spectrum to whichcertain energy scattering layers may be made to appear opaque toparticular wavelengths of non-visible radiation.

Additionally, reference to any particularly useful compositions of thematerials from which the disclosed substantially transparent multi-layermicron-sized particles, which may be generally spherical, may be formedare also descriptive only of broad classes of input materials that maybe presentable in generally transparent, or seemingly transparent,particle form. Suitable materials for such particles may be discussedspecifically according to their composition, or may be more broadlyreferred to by certain functional parameters (including variablerefractive indices), neither of which should be considered to limit thebroad scope of available input materials of which such particles may beformed. Typical particle sizes may be on an order of 5 microns or less,and thus comparable in size to pigment particles typically found inpaints or colorants. See Table 1 below.

TABLE 1 average pigment particle size microns meters representativepigments  50 μm smallest particles visible without magnification cobaltviolet manganese blue 10 μm 10⁻⁵ cobalt green cobalt turquoise ceruleanblue manganese violet black iron oxides  5 μm ultramarine blue (RS)viridian cobalt blue violet (brown) iron oxides yellow iron oxides  1 μm10⁻⁶ ultramarine blue (GS) red iron oxides cadmium red cadmium orangesemiopaque synthetic organics diarylides pyrroles naphthols perinoneorange 0.5 μm  =500 nanometers =wavelength of “blue green” lightchromium oxide green cadmium yellow bismuth yellow titanium whitetransparent red iron oxides transparent yellow iron oxidessemitransparent synthetic organics Note: Particle measurements areapproximate and represent the average of a distribution of pigmentgrades; sizes quoted here are representative of modern artist'spigments. All pigment particles tend to clump into aggregates oragglomerates, which may be 5 to 50 times larger than the sizes listedhere. Sources: Handbook of Industrial Chemistry (1999); Gettens & Stout,Painting Materials (1956); Artists' Pigments (1996-2005); KremerPigments; manufacturer data.

As will be described in greater detail below with, for example,reference to FIG. 5, the disclosed particles may each comprise aspherical core or nucleus, and as many as 30+ layers surrounding thatcore or nucleus to achieve the particular control of the refractiveindex of each of the particles in the manner indicated in thisdisclosure. The composition of the substantially transparent multi-layermicron-sized particles will be controlled generally depending onwavelength of the incident energy that is intended to be scattered bythe energy scattering layer comprising the particles. Table 2 refers toranges of wavelengths for the differing colors in the visible lightspectrum.

TABLE 2 Color Wavelength Frequency Photon energy violet 380-450 nm668-789 THz 2.75-3.26 eV blue 450-495 nm 606-668 THz 2.50-2.75 eV green495-570 nm 526-606 THz 2.17-2.50 eV yellow 570-590 nm 508-526 THz2.10-2.17 eV orange 590-620 nm 484-508 THz 2.00-2.10 eV red 620-750 nm400-484 THz 1.65-2.00 eV

Typical dielectric matrices in which such particles may be stabilizedwill be described. These may include binder or matrix materials that maybe generally comprised of synthetic or natural resins, such as alkyds,acrylics, vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes,polyesters, melamine resins, epoxy, silanes or siloxanes or oils. Anyreference to a particular transparent dielectric material to promote thestabilization or fixing of the particles in layer form is intended to beillustrative and non-limiting.

An advantage of the compositions described in this disclosure over thosedescribed in the 143 and the 145 applications is that the composition ofthe substantially transparent multi-layer micron-sized particlesthemselves renders them amenable to suspension in a broader range ofmatrix or suspension formulations.

In embodiments, an object, outer surface coating for an object, and/orouter film may be provided that is designed to allow a wide range ofchosen colors to be presented to an observer from a viewing, observationor light-incident side of the object while substantially maintaining anefficiency of any embedded sensor or photocell as though covered by anyessentially clear, light transparent covering, coating or protectiveouter layer.

In embodiments, virtually any total or partial object surface may bemodified such that photocells or other sensors and devices associatedwith the object surface may be completely masked or camouflaged. A roofon a structure, for example, may be covered by photocells or TFPV, butstill have an appearance of a typical shingled, tiled, metal, tarred orother surface-treated roof. Separately, a portion of a wall of astructure, internal or external, could be embedded with photocells orcovered with TFPV, while maintaining an appearance of a painted surface,a textured surface, or even a representation of a particularly-chosenpiece of artwork, based on being over sprayed with a light-scatteringlayer including transparent particles having selective refractiveindices suspended in compatible matrices for delivery, including byspraying over the photocells or TFPV. Vehicles, including automobilesand/or buses, may be provided with photocells or TFPV on various outersurfaces, the photocells being masked by overcoats of the lightdirecting and/or light scattering layers so as to render the affectedsurfaces as appearing to consist of nothing more than normal, paintedsurfaces.

Outer surface layers of structures, vehicles or objects may incorporatea plurality of different sensors that are masked or camouflaged so as tobe visibly undetectable, or in a manner that is aesthetically correct,pleasing or required according to restrictions in an operatingenvironment or use case. In this regard, a required or desiredappearance of an outer layer of a structure or structural component maybe preserved, while providing advantageous use of a light transmissiveproperty of an object or object surface layer to promote illumination ofan area behind, beyond, under, or around the object or object surfacethat maintains the conventional or desired appearance.

Solid object body structures, hollow object body structures, or otherobject surface layers may be produced that are colorizable, or visuallytexturizable, without the use of pigments, paints, inks or other surfacetreatments that merely absorb certain wavelengths of light. Thedisclosed energy/light scattering layers allow determined visible,near-visible or non-visible wavelengths of energy/light to pass throughthe layers substantially unimpeded, while scattering other determinedvisible, near-visible or non-visible wavelengths of energy/light thus,in the case of visible light scattering for example, producing acolorized look to the surface of the objects that include or incorporatethe energy/light scattering layers.

FIG. 1 illustrates a schematic diagram 100 of an exemplary objectenergy/light scattering surface layer 110 disposed on a transparentportion of a body structure 120. As shown in FIG. 1, the energy/lightscattering layer 110 is configured to allow first determined wavelengthsof energy/light, WLp, to pass through the energy/light scattering layer110. The configuration of the energy/light scattering layer 110simultaneously causes certain second determined wavelengths ofenergy/light, WLs, to be scattered back in an incident directionsubstantially as shown.

As is noted above, and as will be described in greater detail below, theenergy/light scattering layer 110 may be configured of substantiallytransparent multi-layer micron-sized particles of varying sizes,substantially in a range of 5 microns or less. The substantiallytransparent multi-layer micron-sized particles may be stabilized instructural or other layers further comprised ofsubstantially-transparent matrix materials including, but not limitedto, dielectric materials. An ability to configure the substantiallytransparent multi-layer micron-sized particles to “tune” the lightscattering surface of the light scattering layer 110 to scatterparticular second determined wavelengths of energy/light, WLs, mayprovide the capacity of the energy/light scattering layer 110 to producea desired visual appearance in a single color, multiple colors, oraccording to an image-wise visual presentation provided by theenergy/light scattering layer 110. Put another way, depending on aparticular composition of the substantially transparent multi-layermicron-sized particles comprising the energy/light scattering layer 110(or multiple layers), one or more colors, textures, color patterns, orcolor-patterned images may be visually produced by the energy/lightscattering layer 110.

In cases where the incident energy includes wavelengths in the visualspectrum, refractive indices of the energy/light scattering layer 110may be selectively tuned based on structural compositions of thesubstantially transparent multi-layer micron-sized particles. Inembodiments in which the energy/light scattering layer 110 is intendedto appear as a single color across a surface of the energy/lightscattering layer 110, the composition of the particle and matrix schemeacross the surface of the energy/light scattering layer 110 may besubstantially identical, or homogenous. In embodiments in which thelight scattering layer 110 is intended to appear in multiple colors,multiple textures, or as an imaged surface, the composition of theparticle and matrix scheme across the surface of the energy/lightscattering layer 110 may be varied, particularly employing differentlyconfigured (or colored) substantially transparent multi-layermicron-sized particles to present surface layer portions with differingrefractive indices thereby appearing as different colors when viewedfrom a light-incident side of the energy/light scattering layer 110.

A light scattering effect of the energy/light scattering layer 110 maybe produced in response to illumination generally from ambient light ina vicinity of; and/or impinging on, the surface of the energy/lightscattering layer 110. Alternatively, the light scattering effect of theenergy/light scattering layer 110 may be produced in response to directillumination generally produced by some directed light source 130focusing illumination on the light-incident surface of the energy/lightscattering layer 110.

In the general configuration shown in FIG. 1, the energy/lightscattering layer 110 is formed over the transparent body structure 120in a manner that allows the first determined wavelengths ofenergy/light, WLp, to pass not only through the energy/light scatteringlayer 110, but also to pass further through the transparent bodystructure 120 in a substantially unfiltered manner that, in a case oflight in a visual range, allows an area or light-activated sensorpositioned in, under, or behind the transparent body structure 120, orbehind the energy/light scattering layer 110 and, for example, embeddedin the transparent body structure 120, to be illuminated by the firstdetermined wavelengths of energy/light, WLp, as though those firstdetermined wavelengths of energy/light, WLp, may have been otherwisecaused to pass substantially unfiltered through a glass, plastic, orother transparent outer covering or protective layer. In this manner,the first determined wavelengths of energy/light, WLp, passing throughthe energy/light scattering layer 110, and the transparent bodystructure 120, may provide significant light energy to simply illuminatean area shadowed by the transparent body structure 120, or to beemployed as appropriate by any manner of light detection component,including any light-activated, light-absorbing light-employing, orotherwise operationally light-involved sensor positioned in or behindall or a portion of the transparent body structure 120. In embodiments,a thickness of the body structure 120 may be reduced to substantially athickness of the energy/light scattering layer 110.

FIG. 2 illustrates a schematic diagram 200 of an exemplary laminatedsubstrate surface energy harvesting component including, as one or moreof the laminate layers, a thin-film photovoltaic layer disposed on asubstrate, and an energy/light scattering layer according to thisdisclosure disposed over the thin-film photovoltaic layer. As shown inFIG. 2, the ambient energy/light in a vicinity of the energy/lightscattering layer 210, or the energy/light directed from an energy/lightsource 230 at the energy/light scattering layer 210, may pass through aclear overlayer 212, which may be in the form of a clear protectivelayer. The clear overlayer 212 may be formed of a glass, a plastic,another energy/light transparent composition (such as a clear coat)and/or of a material from which a transparent body structure may besubstantially formed. The energy/light scattering layer 210 may beconfigured to operate in a same manner as the energy/light scatteringlayer described above with reference to FIG. 1. At least firstwavelengths of energy/light, WLp, may pass through the energy/lightscattering layer 210, while at least the second wavelengths ofenergy/light, WLs, may be scattered back in the incident direction inthe manner described above.

The at least first wavelengths of energy/light, WLp, may impinge on aTFPV material layer 214 that may be disposed on, or adhered to, asurface of a substrate 220. The at least first wavelengths ofenergy/light, WLp, impinging on the TFPV material layer 214 may causethe TFPV material layer 214 to generate electrical energy, which may bestored in a compatible energy storage device 240 and/or output via acompatible energy interface circuit 250 to deliver the generatedelectrical energy to downstream components or loads (not pictured).

FIG. 3 illustrates a schematic diagram 300 of an exemplary autonomouscomponent that may be usable for remote deployment and surveillancescenarios including an energy-harvester power element 340, a lightsensitive (or other physical parameter measuring) sensor element 350, aprocessor 370, a data storage device 375 and communication capabilitiesmounted in a structural body member 320 having a surface constituted ofa light scattering surface layer 310 according to this disclosure. Asshown in FIG. 3, at least first determined wavelengths, WLp, of theambient light in a vicinity of the light scattering layer 310, or oflight directed from a light source 330 at the light scattering layer310, may pass through the light scattering layer 310, in the mannerdescribed above with reference to the embodiment shown in FIGS. 1 and 2,while at least second determined wavelengths, WLs, of the ambient light,or the directed light, may be scattered back in the incident directionin the manner described above.

The at least first wavelengths, WLp, of the ambient light, or thedirected light, may be caused to impinge on a facing or facial surfaceof the exemplary an energy-harvester power element 340, which may be ina form of a photocell or a TFPV material covered component. The at leastfirst wavelengths of energy/light, WLp, impinging on an energy-harvesterpower element 340 may cause the energy-harvester power element 340 togenerate electrical energy which may be stored in a compatible energystorage device 360 allowing the combination of the energy-harvesterpower element 340 and the compatible energy storage device 360 to powerother components in the exemplary autonomous component.

The at least first wavelengths, WLp, of the ambient light, or thedirected light, may be caused to impinge on a facing or facial surface(or a lens) of an exemplary light sensitive sensor element 350. At leastthe first wavelengths, WLp, of the ambient light, or the directed light,may cause the exemplary light sensitive sensor element 350 to generate aparticular output signal, which may be output directly, or via somemanner of sensor interface 365, to a processor 370 for signalprocessing.

The first wavelengths of energy/light, WLp, impinging on the exemplarylight sensitive sensor element 350 may be conditioned through one ormore energy/light focusing/filtering layers that may be in a form ofoptical isolators, prisms, lenses or the like, and that may focus,filter or otherwise condition the first wavelengths of energy/light,WLp, as may be appropriate to modify an input of the energy to theexemplary light sensitive sensor element 350 to be compatible with thecapabilities, or input requirements, of the exemplary light sensitivesensor element 350, particularly when provided in the form of a cameraand/or other imaging device. Those of skill in the art will recognizethat the first wavelengths of energy/light, WLp, may require minormodification and/or re-filtering to be rendered compatible.

In embodiments, the first wavelengths of energy/light, WLp, may also orotherwise be partially blocked from further transmission to and throughthe transparent body structure 320 by one or more opaque, near opaque,or darkened energy/light shades, which may be in a form of solid objectbody components. The energy/light shades may substantially shield orshadow portions of the transparent body structure 320, and any area orsensor placed behind the energy/light scattering layer 310 in thetransparent body structure 320 from exposure to the first wavelengths ofenergy/light, WLp. Energy/light filtering layers (or elements) andenergy/light shades may be arranged in any configuration to functionexclusively, or otherwise to function cooperatively, to control and/orotherwise direct the transmission of the first wavelengths ofenergy/light, WLp, through the transparent body structure 320 to one orboth of the energy-harvester power element 340 and the exemplary lightsensitive sensor element 350.

The data storage device 375 may be provided to store operating programsto be referenced by the processor 370 in carrying out functional controlof the exemplary autonomous device. Separately, the data storage device375 may be provided to at least temporarily store information obtainedvia the exemplary light sensitive sensor element 350, and as may bemodified by the sensor interface 365.

A wireless communication capability may be provided with the inclusionof a wireless communication interface/transmitter 380, which may be in aform of a low-power radio or satellite communication transmitteroperating according to any one or more of a number of wirelesscommunicating protocols, including such protocols as may be usable tocause the exemplary autonomous device to communicate with similarlysituated autonomous devices to form an ad hoc wireless communicationmesh network between such similarly situated autonomous devices. Asindicated, the wireless communication interface/transmitter 380 mayoperate according to any compatible wireless signal processing protocolincluding, but not limited to, Wi-Fi, WiGig, Bluetooth®, Bluetooth LowEnergy (LE) (also referred to as Bluetooth® Smart or Version 4.0+ of theBluetooth® specification), ZigBee®, or other similar wireless signalprocessing protocol for communication of wireless signals to appropriatelocal or remote compatible receivers.

FIG. 4 illustrates an exemplary embodiment of a detail of anenergy/light scattering layer 400 according to this disclosure. Thedisclosed schemes, processes, techniques or methods may produce anenergy/light scattering layer 400 created using substantiallytransparent multi-layer micron-sized particles 420 in range of diametersof 5 microns or less embedded in a substantially-transparent dielectricmatrix 410. As an example, the substantially transparent multi-layermicron-sized particles 420 may include titanium dioxide nanoparticles ina layered form as described below with regard to FIG. 5, Titaniumdioxide is widely used based on its brightness and comparatively highrefractive index, strong ultraviolet (UV) light absorbing capabilities,and general resistance to discoloration under exposure to UV light.

In earlier experimentation with similar energy/light scattering layers,colorations of the layered materials were achieved through combinationsof (1) material compositions of the particles, (2) material compositionsof the binders, (3) nominal particle sizes, (4) nominal particlespacings, and (5) interplay between any or all of those materialfactors. That “interplay” is important. To any extent that those layerscould be randomly formed, there had to be some order to that randomnessin order to achieve consistent results. In the substantially transparentmulti-layer micron-sized particles according to this disclosure, theonly variables to be controlled are particle size and/or physicalcomposition. Embodiments of the disclosed substantially transparentmulti-layer micron-sized particles are layered, and considered as aunit. There is no requirement for constituent interplay between theparticles and the binder. The binder just holds the particles where theyland, and spacing between the particles is rendered based on a clear,neutral outer coating on the substantially transparent multi-layermicron-sized particles. These modifications provide broader latitude inthe use of randomized delivery methods, including spray delivery of anaspirated composition of non-pigment particulate material suspended in acomparatively transparent or relatively clear binder material. Aspiratedand aerosol delivered solvent suspended particulate material cannotnecessarily be controlled in its delivery, so the composition of thedisclosed substantially transparent multi-layer micron-sized particlesaddresses that issue.

FIG. 5 illustrates a schematic diagram 500 of an exemplary detail of asubstantially transparent multi-layer individual micron-sized particleusable in a light scattering layer according to this disclosure. Thesubstantially-transparent micron-sized particles of the disclosedembodiments are comprised of layered constructions as shown. It isanticipated that the particle shape will be nominally spherical. A coresphere 510 may have a diameter to accommodate an optical path lengththrough the core of approximately one half wavelength of light for thecolor of interest. See Table 2 above. The multi-layer structuresurrounding the core sphere 510 may be comprised of 15 or moreindividual material layers 520-580, each having a thickness toaccommodate an optical path length through the layer of one quarterwavelength of light for the color of interest. For individualized colorsfrom blue to red this layer-on-layer construction surrounding the coresphere 510 may result in an overall particle size of from about 1.9microns up to 2.6 microns. With reference again to Table 1 above, thisrange of overall particle sizes for the multi-layered construction ofthe transparent spheres is comparable to the typical ranges of diameterof paint pigment particles. In other words, the disclosed substantiallytransparent multi-layer micron-sized particles fit well within thenormal range for paint pigment sizes at the upper end of thedistribution for aerosol application of paint.

Apparent colors, patterns or images of light scattering layers may beproduced by adjusting refractive indices of the particles according to asize of the spherical core 510 of the particles and the layers 520-580of material deposited on the spherical core 510 of the particles.Apparent solid colors may be produced by presenting a substantiallyhomogenous layer of single-color particles across a light incidentsurface of the light scattering layer. Patterns may be produced byappropriately varying the adjustment of the refractive indices of theparticles by manipulating the sizes of the spherical cores andaccompanying outer layers of the particles and mixing varying coloredparticles across the light incident surface of the light scatteringlayer, in a manner that may be similar to mixing paint colors in animage-wise variation across a substrate surface.

Each layer 520-580 may exhibit a consistent index of refraction forprimary color particles, or different indices of refraction to vary thecolors consistently in the layered structure of the particles. Thenumber of particle layers may be varied over a range required by aparticular application and/or use case. Such a particle compositionallows for additional degrees of freedom in adjusting the color,transmission and scattering, i.e., in “tuning” the energy/lightscattering effects produced by the composition of the energy/lightscattering layer. Typically, an outer layer 590 will be formed of aneutral, substantially transparent, often dielectric material of athickness selected to provide a minimum required separation between the“colorant” layers of the substantially transparent multi-layermicron-sized particles to reduce instances of refractive interferencethereby causing variation in the color presentation provided by thelight scattering layer.

As employed according to the disclosed schemes, titanium dioxide may bepresented as a substantially-transparent semiconductor material with awide band gap (Eg=3.2−3.4 (eV)) and a high refractive index (n=2.5−2.9).These characteristics allow the titanium dioxide to be used inconjunction with substantially transparent metal dielectric compositesdesigned to obtain, or otherwise control, desired optical properties ofthe energy/light scattering layer in the visible, and near-visual, lightrange. Titanium dioxide should, therefore, be considered to represent anexample of a dielectric material from which the transparent core sphere510 and the transparent layers 520-580 may be formed.

For finding suitable materials for the core and layers, the opticalbandgap may be referenced in conjunction with the material processingrequirements to ensure that the precise dimensional control describedabove is possible. Processing requirements of the layers must becompatible to avoid degradation. Typical band gap values for certainmaterials are comparatively shown in Table 3 below. Diamond is clearwith a high optical band gap and silicon has a low bandgap and isbasically black.

TABLE 3 Band gap (eV) Group Material Symbol @ 302K IV Diamond C 5.5 IVSilicon Si 1.11 IV Germanium Ge 0.67 III-V Gallium nitride GaN 3.4 III-VGallium phosphide GaP 2.26 III-V Gallium arsenide GaAs 1.43 IV-V Siliconnitride Si₃N₄ 5.0 IV-VI Lead sulfide PbS 0.37 IV-VI Silicon dioxide SiO₂9 Copper oxide Cu₂O 2.1

Referencing the photon energy values in Table 3, materials selection forthe particle cores and layers may be according to Table 4, the criterionbeing that the optical band gap exceeds the photon energy of light inthe color of interest.

TABLE 4 Band gap Group Material Formula (eV) IV Diamond C 5.47 IVSilicon carbide, 4H—SiC SiC 3.3 IV Silicon carbide, 6H—SiC SiC 3.0 VISulfur, a-S S₈ 2.6 III-V Boron nitride, cubic BN 6.36 III-V Boronnitride, hexagonal BN 5.96 III-V Boron nitride nanotube BN ~5.5 III-VBoron arsenide B₁₂As₂ 3.47 III-V Aluminium nitride AlN 6.28 III-VAluminium phosphide AlP 2.45 III-V Gallium nitride GaN 3.44 III-VGallium phosphide GaP 2.26 II-VI Cadmium sulfide CdS 2.42 II-VI, oxideZinc oxide ZnO 3.37 II-VI Zinc selenide ZnSe 2.7 II-VI Zinc sulfide ZnS3.54/3.91 II-VI Zinc telluride ZnTe 2.25 I-VII Cuprous chloride CuCl 3.4Oxide Titanium dioxide, anatase TiO₂ 3.2 Oxide Titanium dioxide, rutileTiO₂ 3.02 Oxide Titanium dioxide, brookite TiO₂ 2.96 Oxide Tin dioxideSnO₂ 3.7 Oxide Barium titanate BaTiO₃ 3 Oxide Strontium titanate SrTiO₃3.3 Oxide Lithium niobate LiNbO₃ 4 Magnetic Nickel(II) oxide NiO 3.6-4.0

As discussed in detail in the 143 and 145 applications, colors ofcomposites containing noble metal inclusions may be tuned based onsurface plasmon resonance (SPR) for the composites in the metallicphase. Light scattering layers comprising films with well separatedembedded metallic nanoparticles, in dimensions smaller than thewavelengths of the exciting light, may be characterized by a peak in thevisible range of the absorption spectra. An ability to control therefractive indices of the substantially transparent multi-layermicron-sized particles by carefully applying layers 520-580 to be onequarter wavelength in thickness according to the color of interestintended to be represented allows tuning of the optical properties ofthe substantially transparent multi-layer micron-sized particlessuspended in a matrix as composite material from which the lightscattering layer may be formed.

Particle size is related to the wavelength of interest, in the mannerdescribed above, in order to determine the color of the substantiallytransparent multi-layer micron-sized particles. Spacing between theparticles is related to the size in order to reduce interference betweenthe refractions of separate particles. The binder index of refractionhas to be different from the particle index of refraction. Because wherethere is a difference in index of refraction (according to Snell's Law),a reflection occurs. When two reflections are spaced properly, theinteraction of multiple reflections is what provides the color.

The outer layer 590 may be configured to ensure that the colorantproducing layers of the particles are kept separated. In an instance inwhich the colorant producing layers touch, no interaction reflection isgenerated. A result of a configuration of a particle according to thisscheme is a particle that acts in a form of a Bragg Reflector. Multipleweak reflections of a same wavelength reinforce each other resulting ina strong reflection of a particular wavelength based on the particlesize, which determines the particle spacing, and the index of refractionalso determines the speed of light which in turn describes the opticalwavelength. A number of particles per unit volume of solvent (matrixmaterial) essentially ensures that the particles always touch.

According to the above particle formation scheme, the entire combinedcharacteristic structure necessary to make the coloration work iscollected into a single multi-layered spherical structure. Put anotherway, each single one of these substantially transparent multi-layermicron-sized particles has all of the features necessary to make thecoloration, including the characteristics of the layers, necessaryparticle spacing, and controllable indices of refraction.

There are only now two key components/concerns, once the entiredistribution structure is formed into a single sphere: (1) there will bean interaction between an index of refraction of the binder or matrixmaterial and an index of refraction of an outermost layer of themulti-layered spherical structure; and (2) a thickness of the outermostlayer of the multi-layered spherical structure must be particularlycontrolled to ensure that a proper spacing is maintained by the colorantcomponent layers of the substantially transparent multi-layermicron-sized particles in order to ensure that there is no opticalinteraction between the colorant component layers of the adjacentsubstantially transparent multi-layer micron-sized particles. Thisoutermost layer will typically be thicker than the underlayers of whichthe substantially transparent multi-layer micron-sized particle iscomprised in order to attempt to ensure that safe separation ismaintained.

If the outermost layer is controlled to be composed of a material thatis at a same index of refraction as the binder or matrix material, theoutermost layer does not do anything in interaction with the binder ormatrix material. The outermost layer will be transparent, and maintainthat transparency when immersed in the substantially-transparent binderor matrix material having a same index of refraction as the outermostlayer of substantially transparent multi-layer micron-sized particles.In this manner, the outermost layers, in their composition andthickness, provide the essential interstitial spacing between thecolorant components so as to assure color fidelity. The layers thusformed will yield only the color that is “built in” to the substantiallytransparent multi-layer micron-sized particles according to thestructure of the color yielding/generating underlayers inward of theoutermost layer in the manner described below.

With enough layers, in a range of 10 to 15, to as many as 30 layers,color concentration would be high enough in each of the particles so asto not require external coloration reinforcement provided by adjacentmulti-layer particles. The outer layers are comparatively clear, as isthe binder or matrix solution, and preferably having a comparativelysame index of refraction as between the material forming the outerlayers and the material forming the binder solution. This is to ensurethat there is no interaction between the particles in the binder, and nointeraction between the particles, specifically the coloryielding/generating components of the particles over a longer distance.The outer layers may be comparatively, e.g., 10 times the thickness ofeach of the underlying dielectric layers.

The disclosed substantially transparent multi-layer micron-sizedparticles may be formed in a very tightly-controlled particle buildprocess. A spherical core may be formed in a material or layerdeposition process such as, for example, an atomic layer deposition(ALD) process, to achieve the substantially transparent multi-layermicron-sized particles according to the disclosed schemes. Particledeposition control systems exist that can be scaled to produce thesesubstantially transparent multi-layer micron-sized particles. Qualitycontrol in the particle build process produces the necessary level ofcolor consistency. There are, however, deposition processes that can becontrolled to the units of nanometers thicknesses.

Yield, time and costs will all be interrelated depending on theprecision of the particle build process. When highest levels of colorprecision (repeatability) are required, the precision with which thoseparticles need to be manufactured is high, with lower yield over alonger time and at a higher cost. When the precision in the repeatablecoloration can be less precise such as, for example, in buildingmaterials as opposed to automotive finishes, higher yields are availableover shorter times at comparatively lesser cost. Put another way, higheryields will be available in shorter times and the cost of throughput ofparticles per pound will be comparatively lower.

The physical thickness (diameter) of the sphere will be adjusted per theindex of refraction of the material(s) from which the sphere is formedto give the correct optical path length. This distinction between aphysical diameter, and an optical path length (or diameter), is adjustedby the index of refraction of the material of which the sphere isformed. In a vacuum, the physical diameter and the optical diameterwould be the same as the index of refraction in the vacuum is 1. Theindex of refraction of typical glass, for example, is in a range ofapproximately 1.4-1.5. As such, the physical thickness will be adjustedbased on an index of refraction in order to achieve a particularwavelength of light based on the material employed.

Uniformity with respect to an optical path length is paramount and iscontrolled so that a thickness of the layers surrounding the core willhave a thickness so that, according to their material composition, eachlayer will accommodate an optical wavelength of one quarter of awavelength of light for the color desired. The physical thickness ofeach layer will be adjusted per the index of refraction of the materialfrom which the layer is formed. The layers may be alternated in high andlow indices of refraction. Layers of a high index of refraction will becomparatively thinner while layers of a lower index of refraction willbe comparatively thicker in order to maintain an optical path length ofa quarter wavelength in each of the deposited layers. Put another way,the quarter wavelength of light will precisely “fit” in each of theselayers. This fitting of the quarter wavelength of light will be based ona combination of the physical thickness of the individual dielectriclayers, and the index of refraction for the material from which each ofthose dielectric layers may be formed. In embodiments, an alternating ofdielectric materials among layers may typically vary betweencombinations of high indices of refraction and low indices of refractionin order that the physical thicknesses of pairs of dielectric materiallayers will be slightly different with respect to one another.Generally, the outermost dielectric layer may be formed of a low indexof refraction (less than 2) material, and formed to be comparativelythicker in order to maintain separation between the colorationcomponents of the multi-layered spherical structures. The low index ofrefraction of that formed outer layer is intended to mirror an index ofrefraction of the substantially clear binder material in which theparticles may be suspended for delivery onto substrate surfaces.

Additionally in embodiments, there may be metallic layers sandwiched inbetween each pair of dielectric layers. A thickness of the metalliclayers may be between 0.01 nm and 10 nm, as long as the metallic layersremain substantially transparent. Typically, these metallic layers maybe on the order of 1 nm (or approximately 10 atoms) in thickness. Thepresence of such metallic layers is intended to enhance reflectivityproperties with respect to the multi-layered structure of the coloryielding/generating layers of the substantially transparent multi-layermicron-sized particles. In a thickness of up to 10 nm, such metalliclayers would remain substantially transparent.

Given that light is electromagnetic phenomenon, it has a stronginteraction with metallic layers as conductors. The presence, therefore,of the above-described metallic layers may significantly enhance thereflection at the individual layers.

An additional benefit is that some additional color tunability isprovided by a structure with variability in the compositions of thevarious layers. It is recognized that there will be some very slight(nearly infinitesimal) increase in the absorption of light based on thepresence of the metallic layers. The benefits in reflectivity andtunability, however, far outweigh any disadvantage from this veryminimal increase in absorption. Indium titanium oxide (ITO) is anexample of a metallic layer that is conductive, yet substantiallytransparent. A typical touch screen on a cellular telephone, forexample, includes an ITO surface.

Depending on a thickness of any included metallic layers, the dielectricindex of refraction may not need to be varied as much in the selectionof the materials for the pairs of dielectric layers. If, in a particularset of material layers, each layer has a same index of refraction, in amanner similar to the manner in which a distributed Bragg reflector orfilter is constructed in a fiber-optic core, a very high reflectionwould be produced at a particular wavelength. Interspersing the metalliclayers allows for the dielectric layers to be each of a similarconstruction with regard to an index of refraction in thickness therebysimplifying the manufacturing process. The variance in thickness amongthe dielectric layers may approach zero in some cases.

Generally, there will not be a metallic layer on the outside surface ofthe substantially transparent multi-layer micron-sized particle. Asindicated generally above, the outer layer should be of a particularthickness (up to 10 times a thickness of the color constituent layers)and with a low index of refraction in order to provide a same index ofrefraction of the binder material and enough thickness in the layer tosupport the required separation between the color yielding/colorgenerating layers of substantially transparent multi-layer micron-sizedparticles.

In a manner similar to quarter wavelength antireflection coating layers,in which a broad response may be narrowed by adding additional layers, aparticular number of quarter wavelength layers over the half wavelengthdiameter spherical core in the substantially transparent multi-layermicron-sized particles may define the sharpness (or single colorprecision) of the generated color response of the substantiallytransparent multi-layer micron-sized particles. A 30 layer particle mayhave a spectral response of about 10 nanometers in width (a narrow red,for example) while a 10 layer particle may have a spectral response ofabout 50 nanometers in width (much broader and combining a spectrum ofhues on either side of a particular primary color). The number of layersin the particle will determine how broad a swath of the spectrum oneither side of the peak is included.

It should be noted that the above discussion is not limited tomonochromatic-only particles in which each of the quarter wavelengthlayers is intended to enhance the single color of the core of themulti-layered spherical particle, i.e., a single color of interest.Rather, the individual quarter wavelength layers may provide variableconstituent hues that cause the finished particles to arrive at somecombination of intermediary colors. Certain colors may be betterperceived, for example, when they are comprised of mixture of differenthues in the constituent layers. A width of the swath of the spectrumrepresented may be varied based on the presence of separate huesrepresented by the quarter wavelength thicknesses of the constituentlayers.

It is also noted that the spectral response of the particles that thedisclosed schemes are intended to portray is with respect to sunlightrather than artificial light. The visible response, i.e., thereflections, will be different as between exposure to artificial lightand to sunlight. Separately, the above discussion is not intended toimply that exemplary embodiments of mixed dispersions of particlessuspended in particular binder or matrix materials are limited tosuspension of single color (monochromatic or mixed) particles in thebinder or matrix. The particles produced according to the disclosedschemes may be held in suspensions that are mixable in the same mannerthat pigment particles are held in suspensions that are mixable toarrive at a broad spectrum of colors. In this regard, individual colorsof suspended particle solutions may be mixed, in a same manner as paintpigments, to arrive at a broad spectrum of color combinations. Accordingto these various alternatives, there is a broader array of options forcolor control than exists, however, in conventional pigmented particlepaint-type solutions.

Any suitable acrylic, polyurethane, clearcoat, or like composed binderor matrix material having a low index of refraction may be adapted tosuspend the layer micron-sized particles for application to a broadspectrum of substrate materials. These may include, but not be limitedto, for example, synthetic or natural resins such as alkyds, acrylics,vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes, polyesters,melamine resins, epoxy, silanes or siloxanes or oils. It is envisionedthat, in the same manner that paint pigment particles are suspended insolution, the substantially transparent multi-layer micron-sizedparticles according to this disclosure may be suspended in solution aswell. Unlike paint pigment particles, however, the optical response ofparticles according to the disclosed schemes will not “fade” over timebecause there is no pigment breakdown based on exposure to, for example,ultraviolet (UV) radiation. The disclosed particles will also besubstantially insensitive to heat.

According to the above, application methodologies that are supportablewith particles according to the disclosed schemes include all of thosethat are available for application of paints, inks and other colorationsubstances to substrates. These include that the particle-suspendedsolutions can be brushed on, rolled on, sprayed on and the like.Separately, the particles may be pre-suspended in the solutions orprovided separately for on-site apparatus mixing into the deliverablesolutions at the point of delivery to a particular surface. Theparticles may be delivered via conventional aspirated spray systemsand/or via aerosol propellants including being premixed with thepropellants for conventional spray can delivery. Finally, the particlesmay be dry delivered to a binder-coated substrate. Conventional curingmethods may be employed to fix the binder-suspended particles on thevarious substrates. A reason that the latitude exists in the deliverymethods, substrates and binder materials is based on the composition ofthe particles themselves, which renders the particular lighttransmissive/reflective properties to the particle solutions and layersproduced therefrom.

In the above-described manner, a finished and stabilized apparentcolored, multi-component colored, texturized or otherwiseimage-developed surface transparent light scattering layer is produced.Mass production of such layers could be according to known delivery,deposition and development methods for depositing the light scatteringlayer forming components on the base structures as layer receivingsubstrates, and automatically controlling the exposure, activationand/or stabilization of the surface components to achieve a particularcolored, multi-colored, texturized and/or image-wise patterned lightscattering layer surface.

Additives may be included in the binder or matrix materials in which thesubstantially transparent multi-layer micron-sized particles are, or areto be, suspended to enhance one or more of a capacity for adherence ofthe formed transmissive layer to a particular substrate, including anadhesive or the like, and a capacity for enhanced curing of the layer,including a photo initiator or the like.

Exemplary light scattering surface layers according to this disclosurewhen viewed in plan form from a viewing, observation or light-incidentside, may present varying colors and/or textures. These may include, butare not limited to: (1) a light scattering surface layer that is formedto scatter a same wavelength of light across an entire light scatteringsurface layer thus producing a single visible color; (2) a lightscattering surface layer that is formed to scatter a first wavelength oflight as a background color, and a plurality of second wavelengths oflight as other color/texture portions within determined areas of thelight scattering surface layer to thus produce some manner of amulti-color and/or textured appearance in the light scattering surfacelayer; and (3) a light scattering surface layer that is formed toscatter a first wavelength of light as a first background color, asecond (or more) wavelengths of light as second intermediate backgroundcolor(s), and a plurality of third wavelengths of light ascolor/texture/image portions within determined areas of the lightscattering surface layer to thus produce some manner of a multi-color,multi-texture and/or image-wise appearance in the light scatteringsurface layer.

In all of the embodiments described above, it should be appreciated thatthe various light scattering layers may be formed in a manner to allowthe first determined wavelengths of light to pass through the lightscattering layers as selected wavelengths in a visible, near-visible ornon-visible range, and to allow the second determined wavelengths oflight to be scattered as selected wavelengths primarily in the visiblerange. The single color, multi-color, multi-textured or image-wisevisual presentations may result from deposition of substantiallytransparent multi-layer micron-sized particles formed or tuned to haverefractive indices in select portions of the overall light scatteringlayers.

FIG. 6 illustrates a schematic diagram of an exemplary assembly linesystem 600 usable for automated forming of energy/light scatteringsurface layers on structural body members including photocell arraylayers according to this disclosure. The exemplary system 600 may beused to prepare and build individual energy/light scattering layers asadditive layers on a base body structure, or as individual layersdisposed on differing substrates.

As shown in FIG. 6, the exemplary system 600 may include a layer formingdevice 630. The layer forming device 630 may comprise a plurality ofspray nozzles or spray heads 631-635, which may be usable to facilitatedeposition of a layer forming material on a surface of an object orsubstrate when positioned in a material deposition position 680.

The layer forming device 630 may be connected to an air source 610 viapiping 615 and may separately be connected to a layer material reservoir620 via piping 625. The layer forming device 630 may be usable to obtaina flow of layer material from the layer material reservoir 620 and intrain that layer material in an airstream provided by the air source 610in a manner that causes aspirated layer material 638 to be ejected fromthe spray nozzles or spray heads 631-635 in a direction of the object orsubstrate when positioned in a material deposition position 680 oppositethe layer forming device 630.

The layer material reservoir 620 may include separate chambers for asupply of substantially transparent multi-layer micron-sized particles,particle supply 622, and for a supply of binder or matrix material,binder supply 624. In embodiments, the particles and the matrix materialmay come premixed, the particles and matrix material may be mixed in thelayer material reservoir 620, or the particles and matrix material maybe separately fed to the layer forming device 630 and mixed thereinbefore being entrained in the airstream provided to the layer formingdevice 630 by the air source 610. It should be noted that, inembodiments, an air source propellant, particles and matrix material mayall be premixed in, for example, an enclosed aerosol container.Separately, it should be noted that, in embodiments, the layer formingdevice 630 may include an articulated arm with one or more spray nozzlesor spray heads 631-635 mounted on a distal end as a layer formingrobotic arm. Additionally, in embodiments, a particle and matrixmaterial mixture may be provided in a material supply reservoir of aconventional spray gun with an air source being provided by a portablecompressor for delivery of the layer material in a delivery operationsimilar to a conventional spray painting of a surface.

The object or substrate may be translatable in direction A to optimallyposition the object or substrate with respect to the layer formingdevice 630, in order to accommodate substrates and objects of varyingsizes for optimal deposition and development of the energy/lightscattering layers thereon.

The object or substrate may be translatable in a direction B between thematerial deposition position 680 and a curing/finishing position 685opposite a layer fixing device 650 that may employ known layer fixingmethods including using heat, pressure, photo-initiated chemicalreactions and the like to cure and/or finish the energy/light scatteringlayers on the object or the substrate. The object or substrate may betranslatable in direction B using, for example, a conveyor transportsystem 640 or other comparable transport system, including but notlimited to, a robotic arm-type material transport device. The conveyortransport system 640, as depicted in FIG. 6, may comprise a series ofconveyor rollers 642, 644 about which a conveyor belt 646 may be made tocirculate. The conveyor transport system 640 may have elements that aremovable vertically in direction A in order to accommodate the layerforming and fixing processes undertaken by the exemplary system 600.

The exemplary system 600 may operate under the control of a processor orcontroller 660. Layer and object forming information may be inputregarding at least one energy/light scattering layer to be formed andfixed on an object or substrate by the exemplary system 600. Thecontroller 660 may be provided with object forming data that isdevolved, or parsed, into component data to execute a controllableprocess in which one or more energy/light scattering layers are formedto produce a single color, a multi-color, texturized surface or animage-patterned presentation when viewed from the viewing, observationor energy/light incident side of a finished energy/light scatteringlayer on a substrate or on a finished object of which the energy/lightscattering layer is a component. The controller 660 may control movementof the conveyor transport system 640 and operation of the layer fixingdevice 650 in addition to controlling the mixture, entrainment anddelivery of the material composition for forming the energy/lightscattering layer.

The disclosed embodiments may include methods for forming alight-scattering layer, as an autonomous structure, or on some manner ofenergy harvesting structural body member, having an opaque outwardappearance based on inclusion of an energy/light scattering surfacelayer formed over a photocell layer according to this disclosure FIG. 7illustrates a flowchart of such an exemplary method. As shown in FIG. 7,operation of the method commences at Step S700 and proceeds to StepS710.

In Step S710, a plurality of particularly-structured substantiallytransparent particles may be formed in a layer build process asdescribed above. The formed particles may represent a multi-layeredstructure having a selectable and controllable index of refraction basedon layering of quarter wavelength dielectric layers and interspersing ofthin metallic layers therebetween. The multi-layered structures for theplurality of substantially transparent particles may then beencapsulated in clear outer layers or shells to produce substantiallytransparent particles having a diameter of 5 microns or less. Operationof the method proceeds to Step S720.

In Step S720, the formed multi-layered substantially transparentparticles may be suspended in a substantially transparent liquefiedmatrix material to form a liquefied mixture. The substantiallytransparent liquefied matrix material may be selected to have an indexof refraction similar to the clear outer layers or shells of thesubstantially transparent particles in order to substantially reduce anypotential for refractive interference between adjacent particles whendeposited on substrate or object surfaces. The substantially transparentliquefied matrix material may include components to aid in adherence ofthe finished energy/light transmissive layers on the substrates orobjects on which those layers are ultimately formed. The substantiallytransparent liquefied matrix material may include components to aid infixing of the substantially transparent particles in the layer,including heat-activated and/or light-activated hardeners. Operation ofthe method proceeds to Step S730.

In Step S730, a surface of a substrate or a surface of an in-processobject body component may be prepared (or conditioned) to receivedeposition of the liquefied mixture. The surface preparation may includedeposition of one or more substantially-transparent matrix componentmaterials, including, but not limited to, dielectric componentmaterials, on the substrate or the surface of the in-process object bodyonto which the plurality of substantially-transparent particles of thelayer forming material may be deposited. Operation of the methodproceeds to Step S740.

In Step S740, a compressed air or other gas source may be provided togenerate an airstream or gaseous stream in which to entrain theliquefied mixture to generate an aspirated liquefied mixture. Asindicated above, the compressed air or other gas source may not beparticularly limited to any class of compressor, bottled pressurized gasreservoir, or other resource including a pump. Virtually any pressurizedair source is contemplated. The sizing of the particles to be less than5 microns expands the latitude by which the substantially transparentparticles suspended in the matrix material may be delivered to thesubstrate or in-process object body structures. Operation of the methodproceeds to Step S750.

In Step S750, the aspirated liquefied mixture may be directed viacompatible nozzles at the prepared surface of the substrate or theobject body structure by directing the airstream of the aspiratedliquefied mixture at the prepared surface. In a delivery process thatmirrors conventional spray painting, the aspirated liquefied mixture maybe deposited on the prepared surface to form an energy/light scatteringlayer that passes certain wavelengths of energy/light through the layerand that scatters other selectable wavelengths of energy/light accordingto the refractive index tuned into the substantially transparentparticles. A multi-layer build process may render a perceptibly singlecolor, multi-color, patterned, texturized or image-wise presentation ofscattered light from the light incident surface based on one or moredelivery passes for depositing the energy/light scattering layeraccording to the above-described schemes. Operation of the methodproceeds to Step S760.

In Step S760, the deposited aspirated liquefied mixture may be developedor finished on the prepared surface of the substrate or in-processobject structure to form the fixed energy/light scattering layerthereon. Operation of the method proceeds to Step S770.

In Step S770, a finishing processing may be applied to the developedenergy/light scattering layer on the substrate or on the finally formedobject. Such finishing processing may include incorporating an outerprotective layer over the energy/light scattering layer on the substrateor on the finally formed object. Operation of the method proceeds toStep S780.

In Step S780, the formed and finished energy/light scattering layer onthe substrate or finally-formed and finished object may be output fromthe forming system. Operation of the method proceeds to Step S790, whereoperation of the method ceases.

The disclosed embodiments may include a non-transitory computer-readablemedium storing instructions which, when executed by a processor, maycause the processor to execute all, or at least some, of the steps ofthe method outlined above.

As is indicated above, refractive indices of the energy/light scatteringlayers can be modified according to a specific mechanism for layereddevelopment of substantially transparent particles that when formed arecomprised of a substantially spherical inner core and as many as 30+dielectric layers applied in a layer forming process over that innercore with the finally formed substantially transparent particles havingoverall diameters in a range of 5 microns or less.

The above-described exemplary particle and material formulations,systems and methods reference certain conventional components, sensors,materials, and real-world use cases to provide a brief, generaldescription of suitable operating, product processing, energy/lightscattering layer forming and object forming environments in which thesubject matter of this disclosure may be implemented for familiarity andease of understanding. Although not required, embodiments of thedisclosure may be provided, at least in part, in a form of hardwarecontrol circuits, firmware, or software computer-executable instructionsto control or carry out the specific energy/light scattering layerforming functions described. These may include individual programmodules executed by processors.

Those skilled in the art will appreciate that other embodiments of thedisclosed subject matter may be practiced in many disparate filmforming, layer forming, laminate layer forming and object formingsystems, techniques, processes and/or devices, including variousmachining, molding, additive and subtractive layer forming andmanufacturing methods, of many different configurations.

As indicated above, embodiments within the scope of this disclosure mayinclude computer-readable media having stored computer-executableinstructions or data structures that can be accessed, read and executedby one or more processors for controlling the disclosed energy/lightscattering layer forming and object forming schemes. Suchcomputer-readable media can be any available media that can be accessedby a processor, general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM, flash drives, data memory cards or otheranalog or digital data storage device that can be used to carry or storedesired program elements or steps in the form of accessiblecomputer-executable instructions or data structures for carrying intoeffect, for example, computer-aided design (CAD) or computer-aidedmanufacturing (CAM) of particular objects, object structures, layers,and/or layer components.

Computer-executable instructions include, for example, non-transitoryinstructions and data that can be executed and accessed respectively tocause a processor to perform certain of the above-specified functions,individually or in various combinations. Computer-executableinstructions may also include program modules that are remotely storedfor access and execution by a processor.

The exemplary depicted sequence of executable instructions or associateddata structures for carrying into effect those executable instructionsrepresent one example of a corresponding sequence of acts forimplementing the functions described in the steps of the above-outlinedexemplary method. The exemplary depicted steps may be executed in anyreasonable order to carry into effect the objectives of the disclosedembodiments. No particular order to the disclosed steps of the methodsis necessarily implied by the depiction in FIG. 7, except where aparticular method step is a necessary precondition to execution of anyother method step.

Although the above description may contain specific details, they shouldnot be construed as limiting the claims in any way. Other configurationsof the described embodiments of the disclosed systems and methods arepart of the scope of this disclosure.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof; may be desirablycombined into many other different systems or applications. Also,various alternatives, modifications, variations or improvements thereinmay be subsequently made by those skilled in the art which are alsointended to be encompassed by the following claims.

We claim:
 1. An energy harvesting system, comprising: an energytransmissive layer arranged over a photovoltaic layer, said energytransmissive layer comprising: a plurality of substantially transparentparticles, each particle comprising: a spherical core comprised of afirst transparent dielectric material, the spherical core having a valueof a physical diameter equal to a half wavelength of a first selectedcolor of light component to be reflected by the particle modified by arefractive index of the first transparent dielectric material; aplurality of material layers disposed radially outwardly from thespherical core, each of the plurality of material layers being comprisedof at least a second transparent dielectric material, and having a valueof a physical thickness equal to a quarter wavelength of at least asecond selected color of light component to be reflected by the particlemodified by a refractive index of the at least the second transparentdielectric material; and an outer coating comprised of anothertransparent dielectric material having a selected index of refraction of2 or less, the outer coating having a thickness that substantiallyeliminates reflective interference between the colors reflected byadjacent particles when in contact with one another; wherein saidplurality of substantially transparent particles are suspended in asubstantially transparent binder material forming said energytransmissive layer; and wherein said photovoltaic layer is disposed in ashadow of said energy transmissive layer such that energy illuminatingsaid energy transmissive layer that is not of said first selected colorof light or said second selected color of light passes through saidenergy transmissive layer and impinges on said photovoltaic layer. 2.The energy harvesting system of claim 1, the plurality of materiallayers being disposed on the spherical core in a layer-by-layerdeposition process.
 3. The energy harvesting system of claim 2, thelayer-by-layer deposition process comprising an atomic layer deposition(ALD) process.
 4. The energy harvesting system of claim 1, the firstselected color of light component being a substantially same color asthe second selected color of light component.
 5. The energy harvestingsystem of claim 1, the first selected color of light component being adifferent color than the second selected color of light component. 6.The energy harvesting system of claim 1, the first transparentdielectric material being a same dielectric material as one of the atleast the second transparent dielectric material.
 7. The energyharvesting system of claim 1, the at least the second transparentdielectric material having an optical band gap greater than a photonenergy of the at least the second selected color of light component. 8.The energy harvesting system of claim 1, the at least the secondtransparent dielectric material comprising a first transparent layerdielectric material and a second transparent layer dielectric material,adjacent layers of the plurality of material layers being formedalternatively of the first transparent layer dielectric material and thesecond transparent dielectric material.
 9. The energy harvesting systemof claim 1, the plurality of material layers comprising at least 15material layers.
 10. The energy harvesting system of claim 1, theplurality of material layers comprising at least 30 material layers. 11.The energy harvesting system of claim 1, the particle having an overallparticle size of less than 5 microns.
 12. The energy harvesting systemof claim 1, the particle having an overall particle size in a range of1.9 to 2.6 microns.
 13. The energy harvesting system of claim 1, thefirst transparent dielectric material and the at least the secondtransparent dielectric material being selected from a group consistingof titanium dioxide, silicon carbide, sulfur, boron nitride, boronarsenite, aluminum nitride, aluminum phosphide, gallium nitride, galliumphosphide, cadmium sulfide, zinc oxide, zinc selenide, zinc sulfide,zinc telluride, cuprous chloride, tin dioxide, barium titanate,strontium titanate, lithium niobate, and nickel oxide.
 14. The energyharvesting system of claim 1, further comprising a plurality of metallicmaterial layers sandwiched between at least some adjacent pairs ofmaterial layers.
 15. The energy harvesting system of claim 14, each ofthe plurality of metallic material layers being between 0.01 nm and 10nm thick.
 16. The energy harvesting system of claim 15, at least one ofthe plurality of metallic material layers being formed of indiumtitanium oxide (ITO).
 17. The energy harvesting system of claim 1,wherein said substantially transparent binder material is characterizedby having an index of refraction equal to the selected index ofrefraction of the outer coating.
 18. The energy harvesting system ofclaim 1, the substantially transparent binder material being selectedfrom a group consisting of synthetic or natural resins, alkyds,acrylics, vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes,polyesters, melamine resins, epoxy, and silanes or siloxanes.
 20. Theenergy harvesting system of claim 1, the substantially transparentbinder material comprising an adhesive that facilitates adherence of thematerial composition to a surface.